VS.NET 2005 service pack 1 installation failure

If you tried to install Service Pack 1 for Visual Studio .NET 2005 (aka KB926601), via Microsoft Update or manually, chances are high that the upgrade failed. The reason is that the deployment MSI package is almost 500M large. Before the actual installation process begins, Windows tries to verify the package. In order to do it it needs to load it into a continuous block of memory. Since even modern machines might not have that much memory available, the process fails and causes the upgrade to fail as well. An error, similar to "Error 1718.